City Hall and the Cubs announced an agreement Sunday to renovate iconic Wrigley Field, a $500 million plan that gets owner Tom Ricketts nearly everything he sought, even as it leaves questions about the impact on rooftop owners and the neighborhood.

The framework, reached over the weekend after weeks of daily closed-door negotiations that capped years of wrangling, clears the way for the Cubs to submit formal plans for the ballpark rehab and a nearby hotel and office building that ownership contends are needed to raise the money necessary to help turn the long-suffering team into a contender.

If all goes as planned, Mayor Rahm Emanuel will have helped engineer a major economic boost for the city without a hit on taxpayers. Ricketts gets more night games and lucrative advertising signs, even if some of his plans were scaled back a bit. Less certain is the plan's effect on owners of rooftop clubs, some of whom could see their views partially blocked as the clock ticks down on their agreement with the team.

The outcome also is less clear for Ald. Thomas Tunney, 44th, who played a key role in negotiations. Although he will get to tout what were billed as improvements in parking and security, the details yet to emerge could affect his political standing.

For the rest of Chicago, the agreement is a signal that the 99-year-old stadium, loved for its old-time charm but reviled for its ancient amenities, will enter a new era that Emanuel characterized as a major victory.

"For nearly a century, Wrigley Field has been a cherished institution in Chicago and the Wrigleyville community, as well as a cathedral of baseball," Emanuel said in a statement put out Sunday by the mayor's office, the Cubs and Tunney. "This framework allows the Cubs to restore the Friendly Confines and pursue their economic goals, while respecting the rights and quality of life of its neighbors. … It will have a long-lasting positive effect on Chicago."

Specific plans must be submitted to the city for approval. The Plan Commission, City Council and Landmarks Commission all will have to hold public hearings. Although the mayor usually wins in such circumstances, it's not uncommon for plans to be altered in the process.

Ricketts acknowledged his plan faces some hurdles. "We are anxious to work with our community as we seek the approvals required to move the project forward," he said in the statement.

The deal was sealed Saturday, five days after the first home game at Wrigley. Ricketts initially set the start of the season as a deadline, but that day passed, and then the team set April 8 as the deadline. Although that day also came and went without an agreement, negotiations continued.

The goal of the city and the team is to get the plans approved by the time the last pitch is thrown at Wrigley on Sept. 25 so work can start right after that. Some of it is expected to take years.

It's also taken years to get to this point. The Ricketts family bought the team from Tribune Co., which still owns 5 percent of the club, in 2009 in a deal valued at $845 million. An initial effort to get a tax subsidy to rebuild the ballpark went nowhere.

But Ricketts' effort gained steam in January when he said he would not need taxpayer help if the city relaxed zoning and landmark restrictions on what he could do inside Wrigley. "We're not a museum," Ricketts declared then. "We're a business."

Perhaps the most substantial changes in the proposed $300 million stadium rehab are a Jumbotron-like screen in left field and a new sign in right field akin to the Toyota sign now in left. The team also could install additional signs within the stadium that would not block the rooftop club views, according to the statement.

Although the city did not announce the size of the left- and right-field signs, sources said that the documents the Cubs will seek a video screen of up to 5,000 square feet, more than twice as large as the vintage, hand-operated scoreboard in center field. The right-field sign would be up to 800 square feet, more than twice the size of the Toyota sign.

The video screen could partly block views from two rooftops, depending on its placement. To minimize that impact and give the Cubs more room to improve the stadium, the parking lane on Waveland Avenue would be removed so the Cubs could push back the left-field wall. Whether right field also would extended onto Sheffield Avenue was not addressed.

One difficulty during renovation talks was getting rooftop owners not to file a lawsuit, and Sunday's announcement did not say whether that issue was settled. The rooftop owners fear new signs proposed for the outfield would obstruct their views into the park.

As part of a contract that expires at the end of 2023, the rooftop clubs give the Cubs 17 percent of their revenue. The rooftop clubs say that contract and the city's Wrigley landmark ordinance prevent the Cubs from putting up signs that block "the uninterrupted sweep of the bleachers."